Home measurement of recoil spring resistance

[New_comer]

Hello all

I'd like to know how you measure your pistol's recoil spring "poundage" using common household materials and gadgets.


Of course, check gun's "yes, it's safe" status


I use rolled cardboard and push the side of my pistol's slide against my bath scale. Now I know that that slide begins to move at 5lbs, terminates at 11 lbs. The buffer spring yields at 10-11 lbs and ends at 23 lbs. Is this method sufficient? Do I have to diassemble the springs and measure them independently of the gun?


Your technique?

 

[Robert Foote]

Short of lab equipment, not sure how you would arrive at a valid figure. Unless your bathroom scale is a lot more accurate than mine at low readings, I don't think I'd place much faith in it as a scientific instrument.

The usual armorer's 'gauge' for this is simply a new, unused stock spring, and springs in service are compared with this. When they take shorter sets, it's time to start considering replacement.

Personally I'm not convinced that swapping stronger/lighter springs around is necessarily a good idea anyway...

 

[weldonjr2001]

What specifically are you trying to accomplish? The only criteria I use to judge how well or poorly my recoil springs are working is the distance the empty brass is ejected. When it increases past where I think it ought to be (past 6 feet or so), I hit gunsprings.com and order more. The Wolff website will tell you what the factory strength was and will offer standard, weaker and stronger "poundages" depending on your needs. For most pistols anyway.

 

[Apple a Day]

Another method

New_comer,
the method you are using may be flawed a little bit by the added friction of the slide. That, and your bathroom scale might be a bit off.
If you want to figure out the spring constant then here is another suggestion:
1)measure the length of your spring at rest, nothing else touching it
2)hang an object of known mass from it and measure the stretched length. You could sit it on top of the spring and get the same effect but that's hard to balance. It should work the same way either direction (Hooke's Law).
3)Use the formula "k(0.5)distance it stretched=weight of the object" where k is the spring constant in pounds/feet. Make sure you take the measurement of distance in feet -Take the number of inches and divide by twelve.

If you have a new spring then do the same thing with it and use as a control group for comparison.

If you don't have something around the house which is of a known, constant weight then make a run to the grocery store and pick up a chunk of meat or produce with the weight marked on the package and use that.

Yes, I'm a science teacher.
Luck

 

[New_comer]

Thanks guys! Lots of info you shared there.

I'm not too keen on getting a "lab-grade" value of my gun's spring constant, just an approximation of the magnitude of forces that a shooter's hand/arms will be subjected to upon recoil. I was thinking that the best measure to knowing the stresses impacted upon my hands during recoil is the approximate deceleration of the slide as resisted by the springs.

In my pistol's case. peak force occurs when the buffer springs are activated beginning at 11 to a maximum of 23 lbs. Beyond that, the gun's frame takes the brunt of the battering, and of course the impulse thru the gun to the hands become very noticeable/irritating.

How is this info useful? I'd imagine that if I were shooting really hot loads, I must exert a push-pull isometric tension at least equal to the 23 lb recoil "moment", considering that the axis of the movement is anchored some distance away with the wrists as the fulcrum. Doing so mitigates the muzzle flip to an extent that follow up shots become faster as the sights re-align quicker.

The lesson: For faster follow up shots, make sure that the isometric tension in holding the gun equals/exceeds the peak recoil force, which in my case is nearly 23 lbs. I tried this already and I feel I could double tap faster if I compress harder. The pistol flops too much if held rather lightly.

Now to determine how it feels to push 23 lbs, balance the same bathscale with the weak hand and push with the strong hand, till it reaches 23-25 lbs. Get a feel of the tension. Now grab your "safety-checked" pistol and recreate the feel of the tension. using your usual two handed push-pull grip. That's how strong you should be holding your gun.

It really gets a bit tiring after some time, thereby the need to keep the upper body in good shape.

Your thoughts?